Spray coating apparatus



Sept. 16, 1969 J. P. MCHUGH SPRAY comma APPARATUS 3 Sheets-Sheet 1 Filed July 31, 1967 I I l l I I l I I I llllr I I I w: Eiom m u wb INVENTOR BYJOHN F. McHUGH M, Gm ma! ATTORNEYS J. P. MCHUGH SPRAY COATING APPARATUS Sept. 1.6, 1969 3 Sheets-Sheet 2 Filed July 31, 1967 INVENTOR BJOHN P. McHUGH uml, emrm ATTORNEYS Sept. 16, 1969 J. P. MQHUGH 3,467,061

SPRAY COATING APPARATUS Filed July 31, 1967 I5 Sheets-Sheet 3 Fig. 6

INVENTOR BJOHN P. McHUGH magma/a4! ATTORNEYS United States Patent 3,467,061 SPRAY COATING APPARATUS John P. McHugh, Indianapolis, Ind., assignor to The Humostan Corporation, Indianapolis, Ind., a corporation of Indiana Filed July 31, 1967, Ser. No. 657,182 Int. Cl. B050 /02, 11/04 US. Cl. 118--123 6 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to coating apparatus, and more particularly to a coating apparatus for sheet-like materials, which apparatus is arranged to prevent the escape of vapors into the area where the materials are being coated.

It is a common practice to spray a lubricating coating onto sheet metal parts before they are formed in dies, the coating being required to facilitate the drawing of the metal by the dies. Generally, the lubricating coating is applied by mixing a lubricant with air to form a vapor which is sprayed upon the sheet metal, thereby to coat uniformly the sheet metal.

The problem with such an arrangement is that once the lubricant is mixed with air to form a vapor, the vapor escapes into the atmosphere. In some cases, depending on the amount of vapor escaping and the type of lubricant being used, this escaping vapor can have a deleterious effect on the personnel involved and on the other equipment being used.

It is a primary object of my invention, therefore, to provide a coating apparatus constructed and arranged to prevent the escape of vapors into the atmosphere. My apparatus can be described as a fog-free recirculating mist applicator. That is, means are provided for producing a vapor which is directed toward the material being coated and additional means are provided for collecting the excess vapors which do not adhere to the material, thereby to prevent the escape of such excess vapors into the atmosphere. The means for directing the vapor toward the material and the means for collecting the excess vapor are contained within a housing which is provided with openings through which the material being coated may enter and leave.

Another object of my invention is to provide such a coating apparatus wherein the means for collecting the excess vapor comprises a vacuum pump which is energized by the flow of gas from the same source utilized to form the vapor. Thus, the only inputs required for my coating apparatus are a pressurized gas source and a liquid source.

Still another object of my invention is to provide a coating apparatus which is ideally suited for applying a coating to both sides of a sheet metal strip.

Still further objects of my invention will appear as the description proceeds.

To the accomplishment of the above and related objects, my invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that change may be made in the specific construction illustrated and described, so long as the scope of the appended claims is not violated.

In the drawings:

FIG. 1 is a front elevation view, partially sectioned, of a preferred embodiment of my coating apparatus;

FIG. 2 is a side elevation view thereof taken from the left-hand side of FIG. 1;

FIG. 3 is an enlarged, fragmentary, sectional view taken from FIG. 1 generally along the line 33 primarily showing the roller structure which supports and guides the work moving through the apparatus;

FIG. 4 is a perspective view of parts of the apparatus, illustrating the manner in which liquid is mixed with gas to form a vapor which is sprayed upon the work passing through the coating apparatus and the manner in which the excess coating fluid is collected and withdrawn from the apparatus, thereby to prevent the escape of vapors into the atmosphere;

FIG. 5 is a sectional view taken from FIG. 1 generally along the line 5-5 to show the structure of the vacuum pump utilized in my coating apparatus;

FIG. 6 is a sectional view taken from FIG. 4 generally along the line 66 to show the structure of a spray nozzle utilized in my coating apparatus; and

FIG. 7 is a fragmentary, sectional view taken from FIG. 1 generally along the line 7-7 to show a means for adjusting the position of the idler roller of FIG. 3.

Referring specifically to the drawings, it will be seen that my coating apparatus, which is indicated generally by the reference numeral 10, comprises a housing 12 including front and back walls 14 and 16, respectively, a top wall 18, a bottom 20 and side walls 22 and 24. The housing 12, which is supported on feet 26, is arranged to receive a strip of material, such as the sheet of metal 27 shown in FIG. 3, which enters through an opening 28 extending across the front wall 14 and which leaves the housing 12 through an identical opening, not shown, in the back wall 16.

Referring to FIGS. 1 and 2, it Will be seen that the opening 28 is bounded at each of its ends by support bars 30 and 32, at its upper edge by an outwardly and downwardly turned lip 34 and at its lower edge by an outwardly and upwardly turned lip 36. The opening in the back wall 16 is identical to the opening 28 and, therefore, a separate description of the opening in the back wall 16 is not required.

The illustrative coating apparatus 10 is arranged to receive strips of sheet metal 27 or the like through the opening 28 in the front wall 14 and to apply a coating to both sides of the strip, the strip leaving the housing 12 through an opening in the back wall 16 which is identical to the opening 28. It will be apparent that the coating apparatus 10 is not limited to the coating of strips of sheet metal and the like and that the novel principles disclosed herein are equally applicable to apparatus for coating other types of work. For instance, the apparatus 10 3 may be used to apply paint, alcohol, silicone, ink, etchants or cleaning fluids.

Roller means, indicated generally by the reference number 40 in FIGS. 1 and 3, are provided for guiding and supporting the work as it moves through the apparatus 10. Specifically, there is a horizontally extending support roller 42 journalled between the forward ends of the bars 30 and 32 and an idler roller 44 disposed just above the support roller 42 and arranged to urge the work downwardly onto the support roller 42, the idler roller 44 being supported for vertically adjustable movement as shown in FIGS. 1 and 3.

Referring to FIGS. 1 and 3, it will be seen that I have provided a bell crank 46, 48 a each end of the idler roller 44, the bell crank 46 being pivotally connected to the support bar 30 by means such as the screw 50 and the bell crank 48 being pivotally connected to the support bar 32 by means such as the screw 52. The idler roller 44 is journalled between the distal ends of the horizontally extending arms 54 of the bell cranks 46 and 48. An adjustment bar 56 is journalled between the distal ends of the downwardly extending arms 58 of the bell cranks 46 and 48. Referring to FIG. 3, it will be seen that the idler roller 44 is movable generally in the direction of the arrow 60 while the adjustment bar 56 is movable generally in the direction of the arrows 62. Adjustment means, indicated generally by the reference numeral 64, is provided for positioning the bar 56 relative to the front wall 14 of the housing 12, thereby to position the idler roller 44 relative to its associated support roller 42.

In the preferred embodiment of my invention, the adjustment means 64 is located at the midportion of the adjustment bar 56 and is arranged so that the adjustment bar 56 can swivel about its midportion to permit one end of the idler roller 44 to move slightly upwardly while the other end of the idler roller is moved or tends to move slightly downwardly.

Referring to FIG. 7, it will be seen that the illustrated adjustment means 64 comprises an adjustment screw 66 which penetrates a midportion of the bar 56 and which is threadedly engaged with the bar 56. The forward end of the screw 66, which is reduced and unthreaded as indi cated at 67, extends freely through an opening, not shown, in an inverted L-shaped bracket 68; the bracket 68 being fastened to the lip 36 by means such as the screw 69. A pair of washers 70 is carried on the reduced portion 67 of the screw 66, one washer 70 being on one side of the bracket 68 and the other washer 70 being on the opposite side of the bracket 68. The forwardmost end 71 of the screw 66 is peened over to secure the screw against axial movement relative to the bracket 68. Thus, when the screw 66 is rotated, the bar 56 is moved relative to the front wall 14.

Roller means, identical to the roller means 40 is provided at the rear of the housing to support and guide the work through the opening in the rear wall 16 corresponding to the opening 28.

It will be apparent that the housing 12 may have any desired length, the length being determined by the width of the work to be coated.

My coating apparatus is adapted to be connected to a pressurized gas source and a liquid source. For purposes of this description, the input tube 76, which leads from any suitable means (not shown) for supplying a gas under pressure, shall be considered the pressurized gas source and the input tube 78, which leads from any suitable means (not shown) for supplying a coating liquid, shall be considered the liquid source. conventionally, compressed air is used as the pressurized gas in spray-type coating apparatus. However, my apparatus is not limited to the use of compressed air and other gases may be used.

In my apparatus 10, I mix gas provided through the tube 76 with liquid provided through the tube 78 in a pair of spray nozzles 80 and 82, the details of the illustrative spray nozzle being shown in FIG. 6.

Each spray nozzle 80, 82 comprises a threaded input opening 84, a venturi 86, an orifice 88, a second threaded input opening 90 and a threaded exhaust opening 92. The pressurized gas is admitted to the nozzle through the opening 84 feeding into the venturi 86 and the liquid is admitted through the opening 90 which feeds into the orifice 88. In a conventional manner, the liquid is mixed with the gas in the orifice 88 to provide vapor emanating through the exhaust opening 92.

Referring to FIG. 4, it will be seen that the tube 78 is connected to a divider tube 94 which is, in turn, connected through a manually-operated control valve 96 to the opening 90 in the spray nozzle and through an identical, manually-operated control valve 98 to the opening in the spray nozzle 82. Thus, the amount of liquid flowing to each of the spray nozzles 80 and 82 can be varied by operating the control valve 96, 98 associated with the spray nozzle.

The input tube 76 is connected through a manuallyoperated control valve, indicated generally by the reference numeral 100, to a divider tube 102, the upper end of which is connected to the input opening 84 in the spray nozzle 80 and the lower end of which is connected to the input opening 84 in the spray nozzle 82. As a matter of convenience, I have provided a pressure indicating device 104 connected to the valve so than an operator can provide a selected gas pressure to the nozzles 80 and 82. A spray tube 106 is connected to the exhaust opening 92 of the spray nozzle 80 and another spray tube 108 is connected to the exhaust opening 92 of the spray nozzle 82. Each of the spray tubes 106 and 108 is provided with a row of perforations 110, the perforations 110 in the tube 106 being arranged to direct the vapor leaving the spray nozzle 80 toward the top surface of the work moving through the apparatus 10 and the perforations 110 in the spray tube 108 being arranged to direct the vapor leaving the spray nozzle 82 upwardly against the bottom surface of the work.

A pair of tube-like exhaust receptacles 112 and 114 is provided for collecting the excess fluid which does not ad here to the work. The receptacle 112 is provided with two rows of perforations 116, one of the rows extending along the top of the receptacle 112 so that the perforations 116 in the row open away from the work moving through the apparatus 10. The second row of perforations 116 in the exhaust receptacle 112 is on the side of the receptacle generally facing the front wall 14 of the apparatus 10.

The exhaust receptacle 114 is preferably provided with one row of perforations 116 which extends along the bottom of the exhaust receptacle 114 to receive liquid col lected in the bottom of the housing 12. Thus, in the illustrative embodiment, both exhaust receptacles 112 and 114 will receive and collect excess vapors which do not adhere to the work and, whenever condensed coating liquid accumulates in the bottom of the housing 12 to a level above the mouths of the perforations in said receptacle 114, said exhaust receptacle will receive and collect such liquid.

In the preferred embodiment of the present invention, the exhaust receptacles 112 and 114 are evacuated by a vacuum pump, indicated generally by the reference numeral 118 and shown in detail in FIG. 5.

The vacuum pump 118 comprises a pump casing, indicated generally by the reference numeral 120, having an input opening 122, an exhaust opening 124 and a second input opening 126. A nozzle, indicated generally by the reference numeral 128, opens into the pump casing as shown in FIG. 5. The nozzle 128 comprises a threaded input opening 130 which feeds into a venturi 132 which feeds into an orifice 134 which is directed out of the exhaust opening 124.

The receptacle 114 is in communication with the pump casing 120 through the fitting 136 and the exhaust receptacle 112 is in communication with the pump casing 120 through a first L-fitting 138 (FIG. 4), a curved tube 140 and a second L-fitting 142. The input opening 130 of the nozzle 128 is connected to the input tube 76 through a T-fitting 144, a manually-operated control valve 146, clearly seen in FIG. 2, a curved tube 148 and a fitting 150 threadedly received in the opening 130. Thus, the pressurized gas source represented by the tube 76 is connected to the two spray nozzles 80 and 82 and also to the nozzle 128 which opens into the pump casing 120.

The nozzle 128 is arranged so that the flow of gas therethrough will evacuate the exhaust receptacles 112 and 114. That is, as the gas expands upon leaving the orifice 134 and moves out of the exhaust opening 124, a vacuum will be created in the casing 120 which will tend to draw fluid from the exhaust receptacles 112 and 114.

The support rollers 42, idler rollers 44, spray tubes 106 and 108 and exhaust receptacles 112 and 114 are all of the same general length and all extend generally horizontally. The spray tube 106 and the exhaust receptacle 112 are positioned directly above the work moving through the apparatus and the spray tube 108 and the exhaust receptacle 114 are positioned directly below the work.

Of course, openings are provided in the side wall 22 for receiving the ends of the spray tubes 106 and 108 and the exhaust receptacles 112 and 114.

Preferably, a flexible drain tube 152 is sleeved over the perimetrally ridged surface 154 of the pump casing 120 to receive the fluids drawn from the exhaust receptacles 112 and 114.

In the preferred embodiment of my invention, I have provided a pair of wipers arranged to wipe the top surface of the work as it moves through the apparatus 10, only the front wiper, indicated generally by the reference numeral 156, being shown in the accompanying drawings. The wiper 156 comprises a pair of plates 158 and 160 arranged to extend across the apparatus 10 and generally parallel to the axis of the support roller 42, the two plates 158 and 160 being held together, as shown in FIG. 3, by conventional means, such as rivets, not shown. Referring to FIG. 3, it will be seen that I have provided a longitudinally extending cut-out 162 along the bottom of the plate 158 and on the side of the plate 158 which is adjacent the plate 160. A rubber-like wiper blade 164, which extends the length of the plate 158, is placed into the cutout 162 so that, when the plates 158 and 160' are riveted together, the wiper blade 164 will be securely fastened between the plates. The wiper 156 is supported in the apparatus 10 for vertically adjustable movement. External adjustment means, indicated generally by the reference numeral 166, are provided for adjusting the vertical position of each end of the wiper 156. In the illustrative embodiment, each adjustment means 166 comprises a screw 168 which is threadedly engaged with a member 169, the member 169 being pivotally connected at its lower end to one end of the wiper 156 by a screw 178. A knob 172 is fastened to the upper end of each screw 168, the upper end of each screw 168 extending through an opening, not shown, in the top wall 18. Thus, by rotatin the knobs 172, the wiper 156 can be adjusted to engage properly the top surface of the work moving through the apparatus 10.

Referring to FIG. 1, it will be seen that I have provided an indicating means, indicated generally by the reference numeral 174, arranged to show the position of each end of the wiper 156. Each indicating means 174 comprises a pointer 176 connected to its respective end of the wiper 156 by the screw 178 and a scale 180 which is positioned alongside the pointer 176. Of course, a vertically elongated opening 178' in the front wall 14 must be provided for each screw 178 so that the screw can move vertically with the wiper 156.

A wiper identical to the wiper 156 extends across the back of the apparatus 10. This rear wiper, which is also provided with external adjustment means identical to the adjustment means 166, is provided to remove any excess coating applied to the top surface of the work moving through the apparatus 10. The forward wiper 156 is provided to prevent any excess liquid from running out the front of the apparatus 10.

What is claimed is:

1. A coating apparatus comprising a housing, means for supporting work for movement through said housing, a pair of spray nozzles, first conduit means for connecting each of said spray nozzles to a source of gas under pressure, second conduit means for connecting each of said spray nozzles to a source of coating liquid, each of said spray nozzles being arranged to mix liquid and gas from such sources to provide a vapor spray emanating from the exhaust end of said nozzle, a perforated spray tube connected to the exhaust end of each of said spray nozzles, each of said spray tubes being disposed within said housing, one of said spray tubes being arranged to direct vapor toward one side of said work and the other of said spray tubes being arranged to direct vapor toward the opposite side of said work, a pair of perforated exhaust tubes arranged to collect excess fluid not applied to said work, one of said exhaust tubes being disposed adjacent said one side of said work and the other of said exhaust tubes being disposed adjacent said opposite side of said work, and pump means for evacuating said exhaust tubes, said pump means comprising a pump casing, a second nozzle opening into said casing, third conduit means for connecting said second nozzle to such gas source, and fourth conduit means connecting each of said exhaust tubes to said pump casing so that, when gas flows through said second nozzle, said exhaust tubes will be evacuated.

2. An apparatus as in claim 1 wherein said means for supporting work comprises roller means having generally horizontally extending axes, wherein said one spray tube and said one exhaust tube are positioned directly above said one side of said work to extend generally horizontally and transversely to the direction of movement of said work, and wherein said other spray tube and said other exhaust tube are positioned directly under said opposite side of said work to extend generally horizontally and transversely to the direction of movement of said work.

3. An apparatus as in claim 2 wherein the perforations in said other exhaust tube are arranged in a row along the bottom of said other exhaust tube, thereby to receive liquid collected in the bottom of said housing.

4. An apparatus as in claim 2 wherein said roller means comprises a pair of horizontal support rollers, one of said rollers extending along the front of said housing and the other of said rollers extending along the back of said housing, an idler roller associated with each of said support rollers and arranged to urge said work downwardly on said support roller, a pair of bell cranks associated with each of said idler rollers, one bell crank being journalled on said housing at each end of each of said idler rollers, each of said bell cranks having a horizontally extending first arm and a'downwardly extending second arm, each of said idler rollers being journalled between associated said first arms, an adjusting bar associated with each of said idler rollers, each of said adjusting bars being journalled between associated said second arms, and adjustment means arranged to position each of said adjustment bars inwardly and outwardly relative to said housing, thereby to establish the spacing between the idler roller and support roller associated with said adjustment bar.

5. An apparatus as in claim 4 wherein said adjustment means comprises screw means threadedly engaging the longitudinal midportion of each of said adjustment bars, each of said screw means being arranged to position selectively the midportion of said adjusting bar on which said screw means is carried inwardly and outwardly relative to said housing, and means for connecting each of said screw means to said housing so that said adjustment bar engaged by said screw means can swivel about its midportion. i

6. An apparatus as in claim 2 further comprising a generally horizontally extending wiper arranged to engage and wipe said one side of said work, said wiper extending transversely to the direction of movement of said work, means for supporting said wiper for vertically adjustable movement, and indicating means arranged to show the position of said wiper.

References Cited UNITED 2,309,251 1/1943 Little 134102 3,382,845 5/1968 Jester 118326 X WALTER A. SCHEEL, Primary Examiner STATES PATENTS 5 J. P. MCINTOSH, Assistant Examiner Miles 118-326 X US. Cl. X.R. Newcornb. 118---316, 326

Eckert 118326 X 

